One problem with teachable trim apparatus is that the cutting head of the apparatus must be accurately positioned at a spaced distance from each of a plurality of premarked points on a master workpiece for inputting data from encoder means to program a trim path into the machine controller. The use of an activated cutting head to establish such points can cause operator discomfort, especially in cases where the trim path is defined along an extended complex line or lines which are difficult to access. Such trim paths often occur on large parts such as the instrument panel for an automobile. In such cases the operator must position the activated head with respect to the point to be taught and must also avoid the energy stream which is applied at the point to be taught.
One example of such cutting apparatus is set-forth in U.S. Pat. No. 4,578,554 issued Mar. 25, 1986 for Laser Welding Apparatus. The apparatus includes a minicomputer for controlling the movement of a welding head which has a nozzle for directing the laser beam against the workpiece. There is no suggestion that the work head be replaced by a simulator that includes tracking and feeler means to assure proper placement of the work head of the apparatus at one of a plurality of premarked points on a workpiece for purposes of inputting the controller with axes point data during a teach mode of controller operation.
U.S. Pat. No. 4,146,924 discloses use of light pens to specify a point in a plane and generate a signal for programming robots. In particular the light beam is sensed by a TV camera to program the position of robot fingers for handling devices. It does not teach a cutting head simulator with the same configuration and dimensions of an operative cutting head on apparatus for trimming a workpiece in which tracking means are provided to maintain a desired space between the simulator and the workpiece and to identify a premarked point to be inputted to a machine controller during a teach mode which establishes a programmed path that will position an operating trim head at a desired focused cutting distance with respect to the workpiece as it trims scrap from production workpieces.
U.S. Pat. No. 3,497,701 discloses the use of fiber optics in a pen for developing display programs. Such pens have also been used in machine control as discussed in U.S. Pat. Nos. 3,498,692; 3,911,270 and 4,109,146. These patents, however, do not discuss how the devices might be modified to or made to function as cutting head simulators for conveniently establishing the points at which a multi-axes controller is to be inputted during a teach mode.
U.S. Pat. Nos. 4,107,721; 4,486,842 and 4,402,053 disclose systems for programming a machine by use of light reflection from an object. They do not discuss a device or system to form a cutting head simulator for conveniently establishing the points at which a multi-axes controller is inputted during a teach mode.